If the server supports Fcc/Sent/etc, default prefs can point to the server. Otherwise, copies and folders prefs should point to Local Folders.

By default this value is set to true via global pref 'allows_specialfolders_usage' (mailnews.js). For Nntp, the value is overridden to be false. If ISPs want to modify this value, they should do that in their rdf file by using this attribute. Please look at mozilla/mailnews/base/ispdata/aol.rdf for usage example.

If the password for the server is available either via authentication in the current session or from password manager stored entries, return false. Otherwise, return true. If password is obtained from password manager, set the password member variable. Read only.